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![Sage Weil](/assets/img/avatar_default.png)
get_user_pages() can return fewer pages than we ask for. We were returning a bogus pointer/error code in that case. Instead, loop until we get all the pages we want or get an error we can return to the caller. Signed-off-by: Sage Weil <sage@newdream.net>
233 lines
4.8 KiB
C
233 lines
4.8 KiB
C
#include <linux/ceph/ceph_debug.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/file.h>
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#include <linux/namei.h>
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#include <linux/writeback.h>
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#include <linux/ceph/libceph.h>
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/*
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* build a vector of user pages
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*/
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struct page **ceph_get_direct_page_vector(const char __user *data,
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int num_pages, bool write_page)
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{
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struct page **pages;
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int got = 0;
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int rc = 0;
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pages = kmalloc(sizeof(*pages) * num_pages, GFP_NOFS);
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if (!pages)
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return ERR_PTR(-ENOMEM);
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down_read(¤t->mm->mmap_sem);
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while (got < num_pages) {
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rc = get_user_pages(current, current->mm,
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(unsigned long)data + ((unsigned long)got * PAGE_SIZE),
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num_pages - got, write_page, 0, pages + got, NULL);
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if (rc < 0)
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break;
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BUG_ON(rc == 0);
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got += rc;
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}
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up_read(¤t->mm->mmap_sem);
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if (rc < 0)
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goto fail;
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return pages;
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fail:
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ceph_put_page_vector(pages, got, false);
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return ERR_PTR(rc);
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}
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EXPORT_SYMBOL(ceph_get_direct_page_vector);
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void ceph_put_page_vector(struct page **pages, int num_pages, bool dirty)
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{
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int i;
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for (i = 0; i < num_pages; i++) {
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if (dirty)
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set_page_dirty_lock(pages[i]);
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put_page(pages[i]);
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}
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kfree(pages);
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}
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EXPORT_SYMBOL(ceph_put_page_vector);
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void ceph_release_page_vector(struct page **pages, int num_pages)
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{
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int i;
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for (i = 0; i < num_pages; i++)
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__free_pages(pages[i], 0);
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kfree(pages);
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}
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EXPORT_SYMBOL(ceph_release_page_vector);
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/*
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* allocate a vector new pages
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*/
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struct page **ceph_alloc_page_vector(int num_pages, gfp_t flags)
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{
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struct page **pages;
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int i;
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pages = kmalloc(sizeof(*pages) * num_pages, flags);
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if (!pages)
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return ERR_PTR(-ENOMEM);
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for (i = 0; i < num_pages; i++) {
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pages[i] = __page_cache_alloc(flags);
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if (pages[i] == NULL) {
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ceph_release_page_vector(pages, i);
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return ERR_PTR(-ENOMEM);
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}
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}
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return pages;
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}
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EXPORT_SYMBOL(ceph_alloc_page_vector);
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/*
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* copy user data into a page vector
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*/
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int ceph_copy_user_to_page_vector(struct page **pages,
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const char __user *data,
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loff_t off, size_t len)
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{
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int i = 0;
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int po = off & ~PAGE_CACHE_MASK;
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int left = len;
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int l, bad;
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while (left > 0) {
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l = min_t(int, PAGE_CACHE_SIZE-po, left);
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bad = copy_from_user(page_address(pages[i]) + po, data, l);
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if (bad == l)
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return -EFAULT;
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data += l - bad;
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left -= l - bad;
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po += l - bad;
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if (po == PAGE_CACHE_SIZE) {
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po = 0;
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i++;
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}
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}
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return len;
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}
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EXPORT_SYMBOL(ceph_copy_user_to_page_vector);
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int ceph_copy_to_page_vector(struct page **pages,
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const char *data,
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loff_t off, size_t len)
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{
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int i = 0;
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size_t po = off & ~PAGE_CACHE_MASK;
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size_t left = len;
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size_t l;
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while (left > 0) {
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l = min_t(size_t, PAGE_CACHE_SIZE-po, left);
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memcpy(page_address(pages[i]) + po, data, l);
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data += l;
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left -= l;
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po += l;
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if (po == PAGE_CACHE_SIZE) {
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po = 0;
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i++;
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}
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}
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return len;
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}
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EXPORT_SYMBOL(ceph_copy_to_page_vector);
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int ceph_copy_from_page_vector(struct page **pages,
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char *data,
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loff_t off, size_t len)
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{
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int i = 0;
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size_t po = off & ~PAGE_CACHE_MASK;
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size_t left = len;
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size_t l;
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while (left > 0) {
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l = min_t(size_t, PAGE_CACHE_SIZE-po, left);
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memcpy(data, page_address(pages[i]) + po, l);
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data += l;
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left -= l;
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po += l;
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if (po == PAGE_CACHE_SIZE) {
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po = 0;
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i++;
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}
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}
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return len;
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}
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EXPORT_SYMBOL(ceph_copy_from_page_vector);
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/*
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* copy user data from a page vector into a user pointer
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*/
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int ceph_copy_page_vector_to_user(struct page **pages,
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char __user *data,
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loff_t off, size_t len)
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{
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int i = 0;
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int po = off & ~PAGE_CACHE_MASK;
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int left = len;
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int l, bad;
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while (left > 0) {
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l = min_t(int, left, PAGE_CACHE_SIZE-po);
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bad = copy_to_user(data, page_address(pages[i]) + po, l);
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if (bad == l)
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return -EFAULT;
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data += l - bad;
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left -= l - bad;
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if (po) {
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po += l - bad;
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if (po == PAGE_CACHE_SIZE)
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po = 0;
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}
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i++;
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}
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return len;
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}
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EXPORT_SYMBOL(ceph_copy_page_vector_to_user);
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/*
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* Zero an extent within a page vector. Offset is relative to the
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* start of the first page.
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*/
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void ceph_zero_page_vector_range(int off, int len, struct page **pages)
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{
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int i = off >> PAGE_CACHE_SHIFT;
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off &= ~PAGE_CACHE_MASK;
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dout("zero_page_vector_page %u~%u\n", off, len);
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/* leading partial page? */
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if (off) {
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int end = min((int)PAGE_CACHE_SIZE, off + len);
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dout("zeroing %d %p head from %d\n", i, pages[i],
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(int)off);
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zero_user_segment(pages[i], off, end);
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len -= (end - off);
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i++;
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}
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while (len >= PAGE_CACHE_SIZE) {
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dout("zeroing %d %p len=%d\n", i, pages[i], len);
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zero_user_segment(pages[i], 0, PAGE_CACHE_SIZE);
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len -= PAGE_CACHE_SIZE;
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i++;
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}
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/* trailing partial page? */
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if (len) {
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dout("zeroing %d %p tail to %d\n", i, pages[i], (int)len);
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zero_user_segment(pages[i], 0, len);
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}
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}
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EXPORT_SYMBOL(ceph_zero_page_vector_range);
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